Base-promoted Homolytic Aromatic Substitution Research Articles

Phenyl Hydrazine as Initiator for Direct Arene C–H Arylation via Base Promoted Homolytic Aromatic Substitution

A simple and efficient direct radical arylation of unactivated arenes is described which uses cheap and commercially available phenyl hydrazine as an initiator. The reaction occurs through a base promoted homolytic aromatic substitution (BHAS) mechanism involving aryl radicals and aryl radical anions as intermediates and offers a practical approach for preparation of an array of substituted biaryls.

ChemInform Abstract: Cross Dehydrogenative Coupling via Base‐Promoted Homolytic Aromatic Substitution (BHAS): Synthesis of Fluorenones and Xanthones.

AbstractA series of fluorenones and xanthones are synthesized by cross dehydrogenative coupling reaction occurring via base‐promoted homolytic aromatic substitution (BHAS).

Room-Temperature Photoinduced Direct C–H-Arylation via Base-Promoted Homolytic Aromatic Substitution

Conceptually different approach toward biaryl syntheses by photoinduced direct C-H arylation of benzene and thiophene in the presence of t-BuOK is reported. The reaction proceeds through photo- and base-promoted homolytic aromatic substitution. The o-, m- and p- substituted ArI, as well as the electron-donating and electron-withdrawing nature of the substituents were found be good to excellent substrates. Heteroaryl, ArBr, ArCl and double C-H arylation were successfully achieved.

Cross Dehydrogenative Coupling via Base-Promoted Homolytic Aromatic Substitution (BHAS): Synthesis of Fluorenones and Xanthones

Cross dehydrogenative coupling reactions occurring via base-promoted homolytic aromatic substitutions (BHASs) are reported. Fluorenones and xanthones are readily prepared via CDC starting with readily available ortho-formyl biphenyls and ortho-formyl biphenylethers, respectively. The commercially available and cheap tBuOOH is used as an oxidant. Initiation of the radical chain reaction is best achieved with small amounts of FeCp(2) (0.1 or 1 mol %).